In displays of notebook PCs, liquid crystal monitors and the like, in order to prevent reflection of the outside scenery on a surface of displays, a mixture of organic or inorganic fine particles and a binder resin or a curable resin is usually applied on a base material to form unevenness on the surface, thus exhibiting antiglare properties. In order to improve antiglare properties, there is a need to increase the shape of unevenness or to increase frequency of unevenness. Large unevenness or an increase in frequency of unevenness enables an increase in haze value (haze degree) of an antiglare layer, thus obtaining antiglare properties. However, there arose a problem that reflection of external light may cause white blur of a screen and an increase in haze value may cause deterioration of image clarity, leading to deterioration of visibility of a display image. Moreover, if the haze value on the surface, which is a general evaluation of a conventional antiglare hard coat film, is lowered, though the degree of white blur of the screen caused by reflection of the external light can be suppressed, glaring brightness referred to as so-called scintillation (glare) becomes strong on the film surface. In order to solve this, a method of increasing the haze value inside the antiglare layer has been used. However, light transmittance is lowered by internal haze caused by a refractive index difference between the fine particles and the resin, which lowers display brightness of the display device, and a coated film becomes whitish due to the internal haze at the same time, thus causing drastic deterioration of contrast.
Japanese Unexamined Patent Application Publication No. 11-326608 (Patent Document 1) discloses an antiglare film in which translucent fine particles having an average particle size of 0.5 to 5.0 μm and a refractive index difference between translucent fine particles and a light transmissive resin of 0.02 to 0.20 are mixed. Patent Document 1 discloses that control of a refractive index difference between a light transmissive resin, which forms the antiglare layer, and translucent fine particles contained therein within a range from 0.02 to 0.20 enables an improvement in image clarity without lowering diffusion/antiglare properties, and also enables maintenance of high image clarity even if the haze value is increased to reduce glaring. However, the specifically obtained film has high antiglare properties with the haze of 10% or more, while the coated film becomes whitish, leading to drastic deterioration of the light transmittance and contrast.
Japanese Unexamined Patent Application Publication No. 2008-286878 (Patent Document 2) discloses as follows. That is, in an antiglare film, since a refractive index difference between a cured material of a binder and translucent fine particles is controlled within a small range from 0 to 0.05, light transmittance inside an antiglare hard coat layer can be improved. Since an arithmetic average roughness (Ra) measured in accordance with JIS B 0601-1994 is controlled within a range from 0.01 to 0.30 μm and an average interval (Sm) of unevenness is controlled within a small range from 10 to 300 μm on the surface of the antiglare hard coat layer, light transmittance can be maintained while exerting light diffusion on the surface (outer face) of the antiglare hard coat layer, and thus the antiglare hard coat layer can exert suppression of glaring and improvement in transmissive clarity in a well-balanced manner. However, the ranges of the arithmetic average roughness (Ra) of 0.01 to 0.30 μm and the average interval (Sm) of unevenness of 10 to 300 μm are not small, and most of the antiglare films formed into a product in the market at present fall within this range. Regarding the specifically obtained film having an arithmetic average roughness (Ra) of 0.1 μm or more, if the value of image clarity measured by an optical comb having a width of 2 mm is less than 70%, and the value of image clarity measured at reflection of 60-degree is 60% or less, antiglare properties may be ensured. However, there remains a problems that glare on a high-definition panel is not sufficiently prevented and a consideration is not made on whitishness of a coating film, leading to drastic deterioration of light transmittance and contrast.